//2009/08/25 14:50:18
#include <iostream>
#include <string>
#include <vector>
#include <map>
#include <queue>
#include <sstream>
#include <algorithm>

using namespace std;

class DietPlan
{
public:
    string chooseDinner(string diet, string breakfast, string lunch)
    {
		string s;
		string eaten(breakfast + lunch);
		for(char c='A'; c<='Z'; c++)
		{
			if(eaten.find(c) != -1 && diet.find(c) == -1) return "CHEATER";
			else if(eaten.find(c) == -1&&diet.find(c) !=-1) s += c;
		}
		return s;
    }
};
